Diet guidelines should push raw veg over cooked, say researchers

An apple a day keeps the doctor away, but the sweet spot for long-term health is “three to four portions” of fruit and veg a day, according to new research.

“Higher fruit, vegetable and legume consumption was associated with a lower risk of non-cardiovascular and total mortality,”​ noted experts involved in a major new global study published in The Lancet. ​That’s not surprising.

However, they also discovered that the “benefits appear to be maximum for both non-cardiovascular mortality and total mortality at three to four servings per day (equivalent to 375–500 g/day)”.​

Is 5-a-day finished?​

The team, led by researchers at the Population Health Research Institute (PHRI) of McMaster University and Hamilton Health Sciences in Hamilton in Canada, used data from the Prospective Urban Rural Epidemiology (PURE) study – which followed more than 135,000 people across 18 countries, tracking their diets for an average of seven-and-a-half years.

They assessed fruit, vegetable and legume consumption and related them to deaths, heart disease and strokes. Do their findings mean the end of the five-a-day recommendations, or indeed the suggestion back in February that this should be doubled to 10-a-day​​? Not at all.

"Our study found the lowest risk of death in those who consumed three to four servings or the equivalent to 375 to 500 grams (g) of fruits, vegetables and legumes per day, with little additional benefit for intake beyond that range,"​ said Victoria Miller, a McMaster doctoral student and lead author of the paper. "Additionally, fruit intake was more strongly associated with benefit than vegetables.”​

The findings are “fairly consistent”​ with current guidelines, said Miller in a video accompanying the study​​, given that a portion tends to be 80g in Europe, so five of these equates to 400g. The study also chimes with the 10-a-day one, in that above five portions the health gains gradually tail off.

Get ready for raw​

That doesn’t mean the guidelines shouldn’t be updated, however. Miller and her team found that raw vegetable intake was “more strongly associated”​ with a lower risk of death compared to cooked fresh produce. However, they didn’t consider the type of cooking involved.

"Dietary guidelines do not differentiate between the benefits of raw versus cooked vegetables – our results indicate that recommendations should emphasise raw vegetable intake over cooked,"​ she explained. This might be particularly important in South Asia, Africa and Southeast Asia where raw vegetables are rarely eaten.

In Europe, the focus could be on legumes, which aren’t commonly consumed. “Eating even one serving per day decreases the risk of cardiovascular disease and death,”​ said Miller, noting that consumption in Europe and the US was “more than five a day”.​

Those involved in the study were only asked once about fruit and veg intake, but this doesn’t mean the findings are not valuable. Given the diversity of the populations assessed – spanning low-, middle- and high-come countries – the results add “considerable strength”​ to the theory that fruit, vegetables and beans reduce disease risk, Miller added.

Indeed, previous research has shown that eating fruits, vegetables and legumes decreases the risk of cardiovascular disease and deaths, but most studies were conducted mainly in North America and Europe with a few from other parts of the world. This study has particular importance for low-income countries where intake is “well below five portions a day”,​ the researchers said.